This invention relates as indicated, to hose clamps.
In Blair U.S. Pat. No. 1,705,895, a hose clamp is disclosed in which a transversely corrugated resilient area or section is provided, so that when the clamp is tensioned by means of a tool, such as a screw driver, it will yield slightly along this corrugated section, and the action of the corrugations will serve to contract the clamp so as to compensate for the shrinkage of the material in the hose, thereby maintaining a water-tight connection at all times.
The clamp of the aforesaid patent is provided at one end with spaced ratchet teeth and at the other end with spaced hooks, so that a screw driver or other tool may be used to place the clamp under tension and thereafter permit the hooks to engage the teeth.
In Heller U.S. Pat. No. 3,189,961, a hose clamp is disclosed, in which the clamp, formed of a resilient material, such as spring steel, is provided between its ends with bends or bent portions which supply spring tension to the clamp when the clamp is applied to a hose. One end of the clamp is provided with spaced slots or perforations and the other end of the clamp is provided with a tongue, so that after the ends are pulled in opposite directions until the required tension is reached, the tongue is caused to enter one of the slots or perforations and become locked therein.
In the Oetiker U.S. Pat. Nos. 3,475,793; 3,520,337 and 3,869,944, a spring tensioned band clamping device is disclosed, formed by a band and at least one tensional spring element made of a material having a high elastic limit so as to preserve the clamping pressure which might otherwise lessen due to aging, etc. The tensional spring elements may be in the form of undulated springs or may be in the form of ear-shaped folds. The ends of the hand are provided with a closing mechanism permitting a preliminary step-wise fitting of the band to the diametric dimensions of the hose or other object to be clamped. This closing mechanism consists, in one instance, of spaced perforations or apertures in one end of the band, and spaced counterhooks in the other end of the band, which engage with the apertures or perforations.
The hose clamps disclosed in the aforesaid Blair, Heller and Oetiker patents are representative of a type of clamp in which the clamp is applied primarily in a step-like manner, that is to say, in a ratcheting type action, one notch or step at a time until the appropriate "level" of tightness is achieved.
Such clamps, although they can be manufactured rather inexpensively, have numerous drawbacks or disadvantages which account for the fact that they are not generally popular in the industry which uses hose clamps.
One of the principal drawbacks or disadvantages is that the clamp tightens in a "step-like" manner, which action, in conjunction with the manufacturing variations in the hose, fitting and the clamp itself, will produce assemblies which will be at various degrees of tightness, and consequently at different levels of effective sealing.
Moreover, because of this step-like fastening design, it is necessary to use either some form of a special application tool or a standard tool which is manipulated through an arc-like movement, rendering it virtually impossible to use this type of clamp in a confined or restricted area.
Finally, this step-like arrangement must provide for some form of a notch and pawl to secure the ends of the band together, a provision which is likely to permit the ends of the band to become accidently disengaged from each other when the band is subjected to vibration and aging.
In another type of hose clamp, known as the "Voss" spring-loaded clamp, a heavy spring is used in conjunction with a nut and a "T" bolt to form an assembly.
A clamp of the "Voss" type has a limited operating range, and if the "T" bolt is made too long in an effort to obtain a greater range, the "T" bolt itself will become the chord of a segmented circle, making it impossible to obtain a circular clamp, and as a consequence, reducing the sealing efficiency of the clamp. Moreover, due to its many component pieces or parts, the clamp cannot be manufactured at low cost.